Breakaway fluid couplings are utilized to protect fluid coupling systems exposed to high tension forces. For instance, breakaway couplings are employed with agricultural implements and fuel tanker trucks wherein the possibility of a vehicle moving away from an implement or tank being serviced by a flexible hose line is possible. In such instance, breakaway fluid couplings are employed to permit the hose line to uncouple upon the hose tension forces reaching a predetermined value, and breakaway couplings normally incorporate self sealing valves which automatically close upon the coupling parts separating.
In the past, breakaway couplings are usually employed with conduits and hose lines of relatively small size having a bore of one inch, or less, and such small couplings normally employ poppet or sleeve valves mounted within the fluid passage which form a restriction to fluid flow. Such restrictions are usually not serious as most breakaway couplings are employed in high pressure hydraulic systems wherein the quantity of fluid being transmitted through the coupling is limited.
It is an object of the invention to provide a breakaway fluid coupling which may be used with large diameter hose or conduits, and wherein the coupling structure permits self sealing valve structure to be employed which is not restrictive to fluid flow through the coupling.
Another object of the invention is to provide a high capacity full flow breakaway coupling wherein the breakaway structure may be incorporated into the general configuration of the coupling parts and does not significantly add to the bulk or radial dimension of the coupling.
Yet another object of the invention is to provide a full flow nonrestrictive breakaway fluid coupling which permits the coupling parts to separate upon a predetermined axial tension force being applied to the coupling parts, and which also permits ready manual operation of the coupling latching mechanism, and yet, high fluid pressures within the coupling do not affect the manual operation of the latching mechanism, and such fluid pressures cannot inadvertently release the latch mechanism.
A coupling in accord with the invention consists of male and female tubular parts which may be mounted upon the end of hose or other fluid conducting structure. Valves are associated with each part, and preferably, the valves are of a pivoted "full flow" type wherein coupling of the valves opens the valve components removing the same from the flow path through the coupling parts wherein the valve adds no restriction to fluid flow through the coupling. In the invention, one of the coupling parts utilizes pivoted valve structure such as disclosed in the assignee's U.S. Pat. No. 4,007,909. A nose extension defined upon the male part engages the pivotal valve portions pivoting the same from the fluid path as the parts are connected.
The coupling utilizes a ball detent type latch system wherein radially movable balls are positioned by a axially displaceable latching sleeve, and selectively maintained within a groove defined in the other part whereby axial displacement of the sleeve between latching and release positions operably engages and disengages the balls from the groove. However, the balls are mounted within an axially displaceable collar defined upon the female part which is biased in a direction opposite to that of tension forces occuring within the coupling, and upon sufficient tension forces being applied to the coupling parts the detent supporting collar is axially displaced relative to the latching sleeve permitting the ball detents to align with the sleeve release recess permitting the detents to be removed from the groove and the coupling parts will separate. Such separation permits the valves of each part to automatically close and prevent spillage.